When calling a mobile terminal in a mobile telephone system, which recently is rapidly spreading, for example, a caller at the calling side dials a communication network access code, which is a specific number such as 030 or 040, and then dials a called party number which specifies the terminal at the reception side. Then, at the communication network (hereinafter referred to as "network") side, a charging unit price, which is a unit price of communication fee, is selected according to the mobile network access code dialed by the caller at the calling side, to make charging. That is, at the network side, the location of the mobile terminal is not determined.
As described above, in the mobile telephone system at present, charging processing is made according to the mobile communication network access code dialed by the caller at the calling side. However, a system for automatically charging according to location information of the mobile terminal can naturally be considered.
In a system in which the location of the mobile terminal is determined at the network side and the charging unit price is determined for charging, the charging unit price must be informed to the caller. This is because the communication fee varies with the location of the mobile terminal. In other words, a communication fee unexpected by the caller may be charged.
The requirement for informing the charging unit price is particularly large when the reception side is a mobile terminal, but in other cases, it will often be convenient if the charging unit price can be known by the caller. If it can be known, the caller will become possible to select, not only calling consciously of the charging unit price, but also not calling depending on the charging unit price.